The MacOS X installation (restore) disc(s) for the '15" PowerBook (Aluminum)', install Jaguar (MacOS X 10.2.x).
How were you able to install Tiger onto the PowerBooks' internal (boot) hard disk drive?
Are you using a retail copy of Tiger (MacOS X 10.4.x) to install Tiger onto either the PowerBooks' boot drive, and / or the LaCie external hard disk drive?; or, are you attempting to use a Tiger installation restore disc from another PowerBook (or other Macintosh) model?